In recent years, interchangeable-lens-type digital cameras have become popular at a rapid pace. The widespread use of such cameras results from the following two backgrounds: user's need for a substitute for a single lens reflex camera of related art; and a greatly increasing demand from users who wish to upgrade from their compact digital still cameras.
An interchangeable-lens-type digital camera accommodates an imaging device larger than that in a compact digital still camera, and users therefore expect higher image quality resulting from effective use of the large imaging device. To this end, a zoom lens having excellent imaging performance is typically essentially required.
On the other hand, many users desire that a zoom lens to be used with a digital camera of the type described above provides excellent convenience. Specifically, users strongly demand a zoom lens capable of handling a variety of imaging conditions, capable of smooth focusing, which is suitable for motion-picture imaging, and being compact, particularly compact to carry.
As an interchangeable lens suitable for size reduction, there is a known two-group zoom lens formed of a first lens group having negative power and a second lens group having positive power sequentially arranged from the object side toward the image side.
Further, a compact digital camera, which is typically required to be more compact, also uses a three-group zoom lens including a third lens group having positive power and located on the image side as well as the two groups described above (see JP-A-2010-122457, for example).
Moreover, as a zoom lens suitable for autofocusing in motion-picture imaging, there is a proposed four-group zoom lens formed of a first lens group having negative power, a second lens group having positive power, a third lens group having negative power, and a fourth lens group having positive power sequentially arranged from the object side toward the image side (see JP-A-2006-208889, for example).